Quiver Math

I am blessed with a lot of good bikes.  I have been collecting them for more than 20 years, but still, I know I have, what most sane folks would call, an excess of bicycles.  But the old ones just keep on working and the new ones fill niches and bring joy.  And in the grand scheme of things, collecting bicycles is much cheaper and healthier than collecting coins or cars.  

So my current quiver contains (in chronological order):

1. 1990 Cannondale Aluminum road bike.  This is mostly used for indoor trainer duty and an occasional mucky day road ride.
2. 1995 Grove Innovations Ti bike.  A titanium, no-holds barred, XTR/S-works 26" hard tail.  It was a premier bicycle in 1995 and my pride and joy while riding in Colorado during grad school.
3. 2006 Masi Team Issue 3VC.  Carbon road bike with SRAM force.  Very light and quick.  I got this used from a semi-pro who gets a new bike each year.  So it was a relative bargain for the quality of bike.  
4. 2007 Masi XC.  An aluminum cross bike with ultegra group and sweet, super light wheels.  Again a bargain scored from my semi-pro friend who road it three times. 
5. 2009 Gary Fisher Superfly 100.  An all-out carbon 29er full susp bike.  The last year GF made bikes before it was absorbed by Trek.  I owe my wife a bike thank you for digging deep in the savings account for this one, but it is a marvelous machine.
6. 2010 Surly Karate Monkey.  I have it built stock as a SS and got it at a deep discount.
7. 2011 Salsa Mukluk.  A shop in MN was closing and liquidating its inventory ... a new bike at 40% off and I couldn't pass up the deal.  

I also own a 1998 Cannondale cross bike which is out on loan to my dad and a 1985 Cannondale M500 mountain bike which was donated to a neighbor who promised to give it love.

Each bike still has its purpose and use.  I use the old C'dale road bike as my indoor trainer.  The carbon road bike is for fast group rides.  The cross bike is one of my most used -- winter training and gravel exploring.  I've hardly been off my KM SS all year: commuting, grocery shopping, century rides, exploring, you name it.  The Superfly100 is the sweetest single track carver and NUE series competitive weapon.  My Mukluk is looking forward to winter snow.  And the old Grove Innovations bike is a special rare frame and a good wet weather trainer.

Now the next step.   I am a computer scientist by training and all these bikes got me thinking about how I use them and which ones I value more.   Much of my professional work involves dimensionality remapping and data compression and I wondered if I could make sense of my quiver using the same analytic tools.

1) My first step was cataloging all the reasons I ride bikes.  I came up with 18 different "uses/properties": group rides, alone rides, road rides, singletrack, gravel, explore, relax, go fast, snow, mountains, flats training, towning, nights, cold, touring, commuting, hill repeats.  It is an arbitrary list, but it accurately represents the kind of bicycling I do and the reasons I own each of these bikes.

2) My next step was to score each bike on a scale of 1 to 10 along each of these 18 properties.   A score of 10 represents a perfect use of this bike, a score of 0 indicates a non-use.  I then normalized the scores so that each property sums to 1.

3)   Then I assigned a multiplicative factor to each property (between 1 and 0) indicating how important that property was to me.  These factors summed to 11.7 (arbitrary) which means I will ultimately have 11.7 points to distribute over the seven bikes.

4) I then compute a "score" for each bike determined by how well it fit each category and how important that category was for me.  Basically a sum of normalized property scores multiplied by the category factors.  Here are my bikes ranked by score:

1. (2.95) KM Single Speed
2. (2.45) Masi Cross Bike
3. (2.02) Salsa Mukluk
4. (1.42) Masi Carbon Road Bike
5. (1.40) GF Superfly 100
6. (0.78) Grove Innovations Mtn Bike
7. (0.68) Cannondale Alum Road Bike

Though not shown here.  I also divided each price (I paid) for the bikes by the score to determine a value coefficient.  Obviously the KM and Cross bike jumped even higher because they already had a high score and came with a low price.  The SF100 dropped more due to the high price tag.

Some observations.  My intuitions were confirmed with my KM SS and Cross bike being my two favorites.  They get the most use and are highly versatile.  And they permit me to do the kind of riding I like to do best -- explore back country roads and gravel paths.  My KM gets extra points for filling commuting duty.   I was surprised how highly my mukluk scored; maybe a product of wishful thinking about snow riding this winter, because I haven't had it that long.  I was surprised by how low my SF100 scored; it brings me a lot of joy, but I mainly use it for singletrack days and I don't get enough of those.  The last two bikes are older bikes that fill a small niche now that they have newer replacements, so I expected those to be at the bottom.

That concludes our lesson in quiver math for today.